Cement or binder material



Patent ed Nov. 9, 1937 I Philip S. P

Westfleld, Masa, assignor to Paper Company, Russell, Mass.,

a corporation of usetts No Dra.

Application January-l5 1936 Serial No. sasos a (of. 134-11) This invention relates to acement or binder material.

More particularly stated, the invention relates to a cement foruniting'or laminating sheets of paper or like material. I I The invention has been developed-more especially for use in laminating paper sheets of the type known as glassine paper which is semitransparent. It should be understood, however, that it is not limited to use with this particular type of paper. I Glassine paper-is a product made from a highly gelatinized or hydrated fibre obtained chiefly fi'om spruce wood, and processed on a regular Fourdrinier wire machine. The paper after be 'ing dried is 'redampened to give a web with approximately 17 to moisture content. It is then passed through the heated rolls of a super calender to convert it to the semi-transparent stage known as glassine.

Paper, suchas glassine paper, when manufactured in relatively heavy weights loses much of its transparency and'two light weight sheets when united or laminated by a suitable transparent cement or binder are much more transparent than a single sheet of equivalent weight. This is partially due to the fact that the paper,

I when finished, has on its surfaces small light i l i l marks known as wire marks. when the sheets are laminated by the use of the cement, the surfaces united lose such marks effecting greater transparency.

Paper sheets have been laminated' by the use of wax, such as paraflin wax, as a binder, such laminated sheets when subjected to a temperature of approximately 180 F. tend to separate and when subiected to low temperatures the binder tends to become brittle and crack. 0bviously, both of theseresults are detrimental and undesirable. v

This invention has for its salient object to provide a cement for laminating sheets of paper or like material, so constituted that it will be effective and will not be rendered ineffective at high or low temperatures. 9

Another object of the invention'is to provide a cement of the character and for the purpose set forth, that can be so used in laminating sheets that the I sheets can be joined or united in a simple and economical manner and without una cement of the character and for the purpose described that will be relatively transparent."-

Another object of the invention is to provide a cement for the purpose described, so constituted that sheets laminated therewith will be moisture proof. I

Further objects will be clear from the following specification.

The invention briefly described consists of a cement compound comprising wax, rosin, rubber and petrolatum. These ingredients when properly proportionedand combined give the desired adhesive quality and produce a moisture resisting or moisture'proof binder. Moreover, the cement does not weaken or permit separation of the sheets when subjected to high temperatures, nor does it crack or become less effective at low tem-: peratures.

The wax found most suitable for use is paraffin wax with an approximate melting pointof 155 F. This wax has the desired moisture proof or moisture resisting properties, but is not a stable bond at higher temperatures, such as 180. Sheets'joined by wax will separate at such tem-, peratures. ible at low temperatures and tends to become Furthermore, the wax is not as flex-'- I hard and crystalline causing the sheets to sepahesive qualities to render the cement or bond- I ing material stable and efiective at high and low temperatures.

Such ingredients were found in rosin and rubber. The former is fluid when melted and has the desired tacklness when-mixed with the proper plasticizers. Rubber gives the cement the desired'stability or eflectiveness under high and low temperature conditions. For a plasticizer, petrolatum with a melting point of approximately F. has been found effective.-

-When a substantially transparent adhesive film is desired, as for instance, for use in uniting or laminating sheets'of glassine paper, the grades of ingredients should be chosen with this .end in view. Thus, for a semi-transparent cement, rosin, such as grade X and rubber in the form or grade of crepe, or pale crepe? should be used.

The ingredients found most adaptable for th .p'urpose specified are, therefore, parafiinwax (melting point approximately ,.F.), .rosln (grade X, preferred), rubber (preferably crepe rubber) and petrolatum (approximate melting point 125 'F.).'

rnese ingredients may be combined in the necessary or desired proportions, the proportions that have given the best results being approximately -63% wax, 20-45% rosin, 13-12% rubpetrolatum. 'I'hese proportions of the specification and provides a stable, effective binder, particularly for uniting or laminating paper sheets. The cement is not adversely affected by changes in temperature and is stable and effective at both high and low temperatures.

Although certain specified ingredients and approximate proportions have been mentioned in the above specification, it will be understood that there is no intention of limiting the invention to the particular and specified ingredients and proportions, but that applicant is entitled to a reasonable range of equivalents and a reasonable variation in the proportions mentioned, without departing from the spirit or scope of the invention as expressed in the following claims.

What I claim is:

1. A cement or binder composed of a mixture of paraflin wax having a melting point of approximately 155 F., rosin, rubber and petrolatum having a melting point of approximately K, said ingredients being thoroughly intermixed and combined in the following proportions, namely, wax 40-63%, rosin 20-45%, rubber 3-12% and petrolatum 743%.

2. A cement or binder composed of a mixture of paraffin wax having a melting point 0! approximately F., rosin, rubber and petrolat'um having a melting point of approximately 125 F., said ingredients being thoroughly intermixed and combined in the following proportions, namely,

wax 60%, rosin 27%, rubber 5% and petro- 3. A cement or binder composed of a mixture of parafiin wax, rosin, rubber and petrolatum, said ingredients being thoroughly intermixed and combined in the following proportions, namely, wax 40-63%, rosin 20-45%, rubber 3-12% and petrolatum 743%.

4. A cement or binder consisting of paraflin wax 40-63%, rosin 20-45%, rubber 3-'-12%, and 

